with open(r"./account.txt", 'w', encoding="utf-8") as file:
  file.write("这是我的账本。")

with open(r"./account.txt", "a", encoding="utf-8") as file:
  file.write("\n2020-02-02，\n今天是妈妈的生日，\n我花了60元给妈妈买了一束康乃馨，\n妈妈很开心，\n我也很开心。\n记得换行哦。")

with open(r"./account.txt", "r", encoding="utf-8") as file:
  print(file.read())